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If you want to know how life works, it makes sense to study Earth's most abundant and simplest organisms: viruses. Biology professor Ken Stedman finds these fast-mutating microbes even in seemingly uninhabitable environments, like the acidic hot springs at California's Lassen Volcanic National Park. By studying these viruses, Stedman's team is furthering our understanding of how life can mutate and evolve.

Ken Stedman and his team find viruses in the strangest places. In doing so, they've also discovered new clues about how life evolved.

Viruses are the most abundant organisms on earth, yet little is known about their evolutionary history since they have exceptionally high rates of genetic mutation that are difficult to track. Viral meta-genomics, however, is becoming an increasingly useful tool with which to glimpse virus evolution, as it makes available vast amounts of new sequence data for analysis.

Stedman, an associate professor of biology and member of the Center for Life in Extreme Environments at PSU, regularly retrieves new microbes from extreme environments like the acidic hot springs at Boiling Springs Lake in California's Lassen Volcanic National Park. This high temperature lake ranges from 126° to a near-boiling 203°F and with an acidic pH of ~2.5, similar to cranberry or lemon juice. Sufficed to say, only the heartiest of microbes can survive in this extreme environment.

Filtering through microbes from one such expedition, Stedman and his students discovered something unique: a hybrid virus incorporating both RNA and DNA structures into its genetic design. "It's a mythological beast of a virus, but it exists," Stedman told reporters.

The finding is significant in demonstrating how viruses may have bridged an evolutionary gap four billion years ago, when life forms evolved from RNA-based genetic material to more complex DNA-based cellular life. When Ph.D. student Geoffrey Diemer and Stedman published results in the June 11, 2012, issue of Biology Direct, their work became one of the journal’s most accessed articles ever.

Stedman and his team cross-referenced the hybrid virus and found similar versions had been captured in ocean water samples—signaling that this combination was not an anomaly. "It's exciting to find out that this isn't just happening here—it's happening everywhere," Stedman says.

The work at Boiling Springs Lake continues with a hunt for the microbes that might host such a virus, and what impacts this virus might have on the overall ecosystem. "Does it kill off the algae? Is it important for amoebae? What is its role and how abundant is it?" says Stedman.

He hopes to bring this work to a broader audience via a documentary, Edge of Life, now in development, which will help showcase the relevance of viruses, and their potential as beneficial partners to humanity.